title: Natural wetlands are efficient at providing long-term metal remediation of freshwater systems polluted by acid mine drainage.
abstract: This study describes the first long-term (14-year) evaluation of the efficacy of an established (>100 years) natural wetland to remediate highly acidic mine drainage (AMD). Although natural wetlands are highly valued for their biodiversity, this study demonstrates that they also provide important ecosystem service functions through their ability to consistently and reliably improve water quality by mitigating AMD. The Afon Goch river flows from Parys Mountain copper mine via a natural wetland, and was the major source of Zn and Cu contamination to the Irish Sea. Prior to 2003 the wetland received severe acidic metal contamination and retained a large proportion of the contamination (55, 64, and 37% in dissolved Fe, Zn, and Cu) leading to a greatly reduced metal flow to the Irish Sea. Reduced wetland loadings midway through the sampling period led to a reduction of metals by 83-94% and a pH increase from 2.7 to 5.5, resulting in long-term improvements in the downstream benthic invertebrate community. High root metal accumulation by the dominant wetland plant species and the association of acidophilic bacteria in the wetland rhizosphere indicate that multiple interacting processes provide an efficient and self-sustaining system to remediate AMD.
authors.affiliation: Faculty of Life Sciences, University of Manchester , Michael Smith Building, Oxford Road, Manchester M13 9PT, U.K.
authors.forename: Andrew P
authors.initials: AP
authors.lastname: Dean
authors.forename: Sarah
authors.initials: S
authors.lastname: Lynch
authors.forename: Paul
authors.initials: P
authors.lastname: Rowland
authors.forename: Benjamin D
authors.initials: BD
authors.lastname: Toft
authors.forename: Jon K
authors.initials: JK
authors.lastname: Pittman
authors.forename: Keith N
authors.initials: KN
authors.lastname: White
mesh_terms: D017753:Ecosystem; D052918:Environmental Restoration and Remediation / Q000379:methods*; D005618:Fresh Water; D008670:Metals / Q000032:analysis; D008906:Mining; D010944:Plants; D012336:RNA, Ribosomal, 16S; D045483:Rivers; D006113:United Kingdom; D014871:Water Microbiology; D014874:Water Pollutants, Chemical / Q000032:analysis; D014876:Water Pollution; D060753:Water Quality; D053833:Wetlands
chemical_list: D008670:Metals; D012336:RNA, Ribosomal, 16S; D014874:Water Pollutants, Chemical